Damper with double floating side rails

ABSTRACT

A damper unit is provided for regulating the flow of hot gases through a duct opening under high ambient temperature conditions. The damper blades are provided with a dual floating side rail arrangement to allow for lateral growth in opposite direction of the damper blades due to thermal expansion.

United States Patent Paredes 5] Oct. 10, 1972 4] DAMPER WITH DOUBLEFLOATING References Cited SIDE RAILS UNITED STATES PATENTS [721 Invenm"Candelam Dallas 3,525,328 8/1970 Crudden ..l26/285 R [73] Assignee:Forney Engineering Company Dallag, Primary Examiner-Charles J. MyhreAttome -John Maier, Ill, Marvin A. Nai ur and John 22 Filed: Feb. 24,1971 E wflsfin g [21] Appl. No.: 118,261

57 ABSTRACT 521 US. Cl. ..126/285 R, 137/601, 251/306 A damper unit isPmvided regulaing 51 Int. Cl ..F23113/00 gases thmugh a duct Waningunder high ambien [58] Field of Search "126/285 R; 98/110; 137/601;temperature conditions. The damper blades are pro- 251/214, 306 308vided with a dual floating s1de rail arrangement to allow for lateralgrowth in opposite direction of the damper blades due to thermalexpansion.

4 Claims, 4 Drawing figures PATENTEDucI 10 m2 SHEEI 1 [IF 2 INVENTOR.

CANDELARIO PAREDES HY y ATTORNEY PATENTEDucI 10 m2 4 3.696, 80 4 sumzmzFIG. 3

INVENTOR. CANDELARIO PAREDES mfi f at ATTORN DAMPER WITH DOUBLE FLOATINGSIDE RAILS BACKGROUND OF THE INVENTION In the operation of large vaporgenerator installations, high temperature precision damper units areused to regulate the flow of hot gases. The damper construction which ismost usually employed consists of a series of damper blades, each ofwhich is individually mounted on a shaft such that the blades can form agastight barrier across a duct opening when in a closed position. Thedamper blades are generally formed with an air foil shaped bladearrangement such that the blades can be positioned side by side in theduct opening to form a barrier to the hot gases when in a closedposition. The damper blades also lend themselves to adjustment intovarious intermediate positions to regulate the flow of hot gases throughthe duct. With this type of aerodynamic blade construction it ispossible to bring the lateral edges of adjacent blades together to forma gas-tight seal. However, due to high temperature conditions, thedamper blades tend to expand and contract along their lateral axis. Thiscan cause leakage of the hot gases as well as binding of the dampershaft I in its bearings, such that free rotational movement of thedamper is constrained.

There has been provided a single sliding rail arrangement for allowingthe damper blade to laterally expand in one direction, as shown in U.S.Pat. No. 3,525,328.

In order to prevent gas leakage and obtain free damper blade rotation,when operating under relatively high and varied temperature conditions,the ends of the damper shaft are each mounted on a floating side railcapable of moving laterally in either direction in accordance with thethermal expansion and contraction of the damper blade along its lateralaxis. In this manner, complete sealing action against the passage of hotgases is provided when the damper blade is in the closed position, andthe damper shaft is capable of rotation in the floating side railsduring these periods of expansion and contraction of the damper blade.

SUMMARY OF THE INVENTION In accordance with an illustrative embodimentdemonstrating features and advantages of the present invention, there isprovided a damper unit for regulating the flow of hot gases which iscapable of operation under high ambient temperature conditions. A framestructure is provided with a central opening and bearing means arespaced apart on the frame in opposing relationship. A pair of shafts arejournaled in the bearing means for rotation, and at least one damperblade is positioned on the pair of shafts and laterally extends acrossthe central opening. The shafts are each provided with a keyway foroperatively engaging the damper blade and to allow for lateral movementof the damper blade with respect to the shafts. The damper blade iscapable of rotation from an open to a closed position for respectivelyallowing the passage and sealing of the hot gases. Positioned in thecentral opening to abut both ends of the damper blade is a pair of siderails having through bores for receiving the shaft. The sealing bars aremounted in the bearing means for lateral movement in both directions inaccordance with the thermal expansion of the damper blade. Thus, theside rail extends laterally in both directions and provides completesealing against the passage of hot gases when the damper blade is in theclosed position.

BRIEF DESCRIPTION OF THE DRAWINGS The above brief description as well asfurther objects, features, and advantages of the present invention willbe more fully appreciated by reference to the following detaileddescription of a presently preferred but nonetheless illustrativeembodiment in accordance with the present invention when taken inconnection with the accompanying drawings wherein:

FIG. 1 is a front elevational view of a portion of a high temperaturedamper unit of the instant invention which is shown completely removedfrom the duct arrangement with the broken lines showing the shaftsincluding the pin and slot arrangement;

FIG. 2 is an enlarged sectional view of the damper unit which is shownin FIG. 1, with portions broken away in order to clearly show the doublefloating side rail arrangement prior to lateral expansion or contractionthereof;

FIG. view similar to FIG. 3' is a partial sectional view of the damperunit shown in FIG. 2 to illustrate the damper blade in a fully expandedposition; and

FIG. 4 is a partial sectional the but with the damper blade in a fullyretracted position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now specifically tothe drawings there is shown in FIG. 1 a damper unit constructionemploying features of the present invention and generally designated bythe reference numeral 10. The damper unit 10 includes a frame structure12 having a central opening 14 with hearing means 16 spaced apart inopposing relationship on frame structure 12. A pair of shafts 18 arejournaled in bearing means 16 for rotation, and damper blades 20 aremounted on shafts 18 to extend laterally across central opening 14. Thedamper blades 20 are capable of being rotated to an open and closedposition for respectively allowing the passage and sealing of hot gases.The bearing means 16 includes a rotational bearing 24 positioned betweena pair of end collars 26. A conventional linkage arrangement which hasnot been shown in the drawings can be mounted on the end of one of theshafts 18 for conjointly moving the damper blades 20.

Positioned in central opening 14 is a double floating side railarrangement, generally designated 30, which abuts the end of damperblade 20. In accordance with the present invention, the double floatingside rail assembly 30 is mounted for lateral movement in accordance withthe thermal expansion of damper blades 20, such that the double floatingside rail assembly 30 extends laterally in either direction with respectto the frame structure 12 and provides complete sealing action againstthe passage of hot gases when damper blades 20 are in the closedposition.

As shown in FIG. 2 the frame structure 12 includes a vertical upstandingsupport 32 and a cover plate support 34 which are jointed together bymeans of welds 36 to form a hollow chamber 38. The supports 32 and 34are provided with aligned bores 40 for receiving the shafts 18.

As previously indicated, the double floating side rail 30 of the presentinvention is an improvement of the single damper floating side rail barof U.S. Pat. No. 3,525,328. Accordingly, the instant double floatingside rail 30 includes a pair of side rail'bars 42 with coupling pin 96and slot means 44 operatively connecting the damper shafts 18 to theside rail bars 42 for lateral movement in either direction.

In FIG. 2 there is shown one of the side rail bars 42 which includes aspring seal 46 mounted on a cylindrical collar 48. The spring seal 46 isintegrally formed with a shoulder 50, through bores 52 and a pair ofupright side walls 54. A pair of stationary sealing angle bars 58 aremounted to the outer face of the upstanding support 32 to form a sealingchannel 62. The side rail bars 42 are fabricated from resilient metalsuch that the upright bars 54 bear against the sides of angle bars 58 insealing channel 62. In this manner, a gas-tight seal is provided betweeneach of the upright side walls 54 and the respective adjacent angle bars58.

Mounted on upstanding support 32 is a'stuffmg box housing 64 which-ispacked with a heavy lubricant 66 and has an axial borewhich is coaxiallyaligned with through bore 40 for rotatably receiving shaft 18. Thestuffing box housing 64 is provided with a cover plate 68 which isremovably secured by through bolts 70.

As best shown in FIG. 2, the damper blade is formed with a horizontal,reinforced edge 72 for coaxially receiving a cylindrical sleeve 74 whichis machined with an internal bearing surface 76 and stop shoulder 78.The cylindrical sleeve 74 can be secured to reinforced edge 72 byvarious conventional means of fabrication such as press-fitting or spotwelding.-

The shaft 18 is integrally formed with an enlarged cylindrical section80, a shoulder 82, and a reduced cylindrical section 84. The enlargedcylindrical section 82 has a horizontal length which corresponds to thesize of hollow chamber 38 and the reduced cylindrical section 84 issized to receive a ferrule bearing 86. The ferrule bearing 86 is formedwith an internal bearing surface 88, which is sizedfor sliding movementon reduced cylindrical section 84, and an annular shoulder 90 formounting the spring seal 46 against the reinforced edge 72 andcylindricalsleeve 74. The shaft 18 also is provided with an elongatedkeyway 92 which is aligned with the horizontal axis of shaft 18. Thereinforced edge 72, cylindrical sleeve 74 and ferrule bearing 86 areformed with vertically aligned through bores 94 which pass throughkeyway 92 for mounting a pin The lateral extremitiesof keyway 92 aredefined by anexpansion edge 97 and a contraction edge 98, and the pin 96is positioned in keyway 92, such that it will bear against expansionedge 97 when the blade 20 is in the fully expanded position and againstcontraction edge 98 when the blade 20 is in the fully retractedposition. This expanded and contracted position of the pin 96 in keyway42 can best be seen in FIG. 3 and FIG. 4, respectively. While thedamperunit 10 has been shown with a single pin 96, it is also possibleto utilize two spaced-apart pins positioned in accordancewith thelateral movement of side rail bars 42 in sealing channel 62 duringthermal expansion and contraction of the damper blade 20.

' By progressively inspecting FIGS. 3 and 4, the manner in which thermalexpansion causes lateral growth to the damper blade 20 on the shafts 18can be appreciated. The damper blade 20 is shown in FIG. 4

prior to the occurrence of thermal expansion and the attendant lateralgrowth, with the spring seal 46 and pin 96 located in the outermostextended position in the sealing channel 62, and keyway 44,respectively. Thus, the pin 96 is brought to rest against contractionedge 98. In accordance with the present invention, the spring seal 46,reinforced edge 72, and sleeve 74, which are mounted on ferrule bearing86, slide laterally in either direction on the shafts 18 due to thermalexpansion and contraction. This can be readily appreciated from themovement of spring seal 46 in sealing chamber 62 and function of the pinand slot means'44 which includes the pin 96 moving in the keyway 94.Thus, in the fully expanded position of FIG. 3, the pin 96 is brought torest against expansion edge 97.

From the foregoing, it can be appreciated that thermal expansion fromintensive heat causes lateral growth to the damper blades 20 on theshafts 18. By providing the pin and slot coupling means 44 and doublefloating side rail assembly '30 located at opposite ends of the damperblade 20, it is possible for lateral growth to occur in both directionswith respect to the frame structure 12. In FIG. 2 the damper unit 10 isshown in a non-expanded position for one side of the unit, while FIGS. 3and 4 illustrated the fully expanded and contracted position of thedamper unit 10. Accordingly, by allowing for lateral growth in eitherdirection along a horizontal axis with respect to frame structure 12,the damper unit 10 in accordance with the present invention affords agas tight seal against the flow of hot gases without impairing the freerotation of the damper blades 20.

A latitude of modification, change and substitution is intended in theforegoing disclosure and in some instances some features of theinvention will be employed without a corresponding use of otherfeatures. Accordingly, it is appropriate that the appended claims beconstrued broadly and in a manner consistentwith the spirit and scope ofthe invention herein.

What is claimed is:

l. A damper unit for regulating the flow of hot gases and capable ofoperation under high ambient temperature conditions comprising a framestructure having a central opening, bearing means spaced apart on saidframe in opposing relationship, a pair of shafts journaled in saidbearing means for rotation, at least one damper blade mounted on saidpair of shafts and laterally extending across said central opening, saidpair of shafts formed with a pair of keyways for operatively engagingsaid damper blade to allow for lateral movement of said damper bladewith respect to said shafts, said damper blade capable of being rotatedto an open and closed position for respectively allowing the passage andsealing of said hot gases, a pair of spaced apart sealing bars mountedon opposite sides of said frame to define sealing channels which arevertically oriented with respect to the horizontal axis of said shaft,and a pair of floating side rails positioned in said sealing channels toabut one end of said damper blade and formed with through bores forreceiving and securing said shaft, said side rails being mounted forlateral movement in either direction in accordance with the thermalexpansion of said damper blade such that said side rail extendslaterally in the direction of said frame and provides complete sealingaction against the passage of hot gases when said damper blade is insaid closed position.

2. A damper unit according to claim 1 in which pins are mounted on saiddamper blade and positioned in said keyways for lateral movement.

3. A damper unit according to claim 1 in which a pin is positioned ineach of said keyways, said keyways having an elongated configuration,such that said pins govern said lateral movement in either direction.

4. A damper unit for regulating the flow of hot gases and capable ofoperation under high ambient temperature conditions comprising a framestructure having a central opening, bearing means spaced apart on saidframe in opposing relationship, a pair of spaced apart shafts journaledin said bearing means for rotation, at least one damper blade mounted onsaid shaft and laterally extending across said central opening, saiddamper blade capable of being rotated to an open and closed position forrespectively allowing the passage and sealing of said hot gases, a pairof side rails positioned in said central opening to abut one end of thedamper blade and formed with through bores for receiving the shaft, apair of upstanding sealing bars mounted on said frame to define asealing channel, said side rails being mounted in said sealing channelfor lateral sliding movement in either direction, each of said shaftsformed with an elongated keyway, and a pin positioned in said keyway andmounted on said damper blade, whereby said side rails extend laterallyin either direction under thermal expansion.

1. A damper unit for regulating the flow of hot gases and capable ofoperation under high ambient temperature conditions comprising a framestructure having a central opening, bearing means spaced apart on saidframe in opposing relationship, a pair of shafts journaled in saidbearing means for rotation, at least one damper blade mounted on saidpair of shafts and laterally extending across said central opening, saidpair of shafts formed with a pair of keyways for operatively engagingsaid damper blade to allow for lateral movement of said damper bladewith respect to said shafts, said damper blade capable of being rotatedto an open and closed position for respectively allowing the passage andsealing of said hot gases, a pair of spaced apart sealing bars mountedon opposite sides of said frame to define sealing channels which arevertically oriented with respect to the horizontal axis of said shaft,and a pair of floating side rails positioned in said sealing channels toabut one end of said damper blade and formed with through bores forreceiving and securing said shaft, said side rails being mounted forlateral movement in either direction in accordance with the thermalexpansion of said damper blade such that said side rail extendslaterally in the direction of said frame and provides complete sealingaction against the passage of hot gases when said damper blade is insaid closed position.
 2. A damper unit according to claim 1 in whichpins are mounted on said damper blade and positioned in said keyways forlateral movement.
 3. A damper unit according to claim 1 in which a pinis positioned in each of said keyways, said keyways having an elongatedconfiguration, such that said pins govern said lateral movement ineither direction.
 4. A damper unit for regulating the flow of hot gasesand capable of operation under high ambient temperature conditionscomprising a frame structure having a central opening, bearing meansspaced apart on said frame in opposing relationship, a pair of spacedapart shafts journaled in said bearing means for rotation, at least onedamper blade mounted on said shaft and laterally extending across saidcentral opening, said damper blade capable of being rotated to an openand closed position for respectively allowing the passage and sealing ofsaid hot gases, a pair of side rails positioned in said central openingto abut one end of the damper blade and formed with through bores forreceiving the shaft, a pair of upstanding sealing bars mounted on saidframe to define a sealing channel, said side rails being mounted in saidsealing channel for lateral sliding movement in either direction, eachof said shafts formed with an elongated keyway, and a pin positioned insaid keyway and mounted on said damper blade, whereby said side railsextend laterally in either direction under thermal expansion.